Means for insuring quiet operation of waste collecting vacuum system



Feb. 12, 1957 F. E. ROWE, JR

MEANS FOR INSURING QUIET OPERATION OF WASTE Filed July 21, 1953COLLECTING VACUUM SYSTEM 2 Sheets-Sheet 1 F. E. ROWE, JR MEANS FORINSURING QUIET 2,781,164 OPERATION OF WASTE Feb. 12, 1957 COLLECTINGVACUUM SYSTEM 2 Sheets-Sheet 2 Filed July 21, 1953 MEANS FGR ENSURINGQUIET OPERATIQN OF WASTE COLLECTING VACUUM SYSTEM Frank E. Rowe, in,Hingham, Mass., assignor to Abiugton Textile Machinery Works, NorthAbington, Mass., a trust of Massachusetts Application July 21, 1953,Serial No. 369,438

7 Claims. (Cl. 23tl115) This invention relates to the provision of meansfor eliminating objectionable noise that has heretofore been an incidentof operation of vacuum systems used in the removal of industrial waste.

While the vacuum system that will hereinafter be explained and withwhich the invention is used has had its principal use in connection withthe cleaning of textile machinery and the like, it will be understoodthat the invention is applicable to any system in which a sufficientlyhigh vacuum is produced by a centrifugal vacuum or suction pump.

in those vacuum or suction cleaning systems of such capacity thatadequate negative pressure can be produced simultaneously at manycleaning points, it is obvious that a large volume of air must becontinuously removed. By the removal of air from the pipes of thesystem, the pressure drops at the cleaning nozzles causing an inrush ofair into the nozzles which carries with it the Waste that is to beremoved. To produce this result, the high speed centrifugal suction pumphas come into general use. This machine is capable of moving asufiicient volume of air to reduce the pressure in the various lines tothe degree necessary to provide an adequate velocity of air into thecleaning nozzles at the various cleaning positions to do a satisfactorywaste removing operation.

in the typical textile factory having various types of machinery to becleaned, such as carding engines, looms, and spinning frames, the vacuumcleaning is not necessarily performed at the same time at each type ofmachine. Accordingly, the suction lines have valves installed atappropriate points which may be opened whenever cleaning is L beundertaken at particular places. The centrifugal pump, however, whichsupplies the necessary suction for all of the cleaning positions willordinarily be operated continuously with the cleaning load varying inaccord With the particular cleaning requirements.

If cleaning is going on simultaneously at all cleaning positions, agreater volume of air will flow through the pump in a unit of time andthe buildup to maximum negative pressure will occur more slowly thanwould be the case if only part of the cleaning mechanism were in use.

it will be understood that air is of an elastic nature and under theinfluence of the continuously operating centrifugal pump, the air in thesuction lines becomes more and more attenuated as the negative pressureincreases. Lik Wise, the pressure differential between the suction anddischarge sides of the pump gradually increases, the discharge sideremaining at a figure slightly above atmospheric. In due course whenthis pressure differential becomes great enough, the atmosphericpressure on the discharge side is large enough to force air backwardthrough the centrifugal pump to the suction side of the pump Where thepressure is so much less The movement of air in a backward directionthrough the centrifugalpump which is rotating at high speed, produces ahigh pitched squeal or shriek which is very objection- 2,781,164Patented Feb. 12, 1957 able to the ear. This squeal is carried in fullvolume to the outlet end of the discharge pipe, which end is customarilylocated outside of the building. This unpleasant sound is of suchfrequency and amplitude that it can be heard for a long distance.

The squeal continues so long as air from the discharge side of the pumpis moving backward past the blades of the pump into the suction system.This reverse movement of air will continue until the pressuredifferential between the suction and discharge sides of the pump isreduced to a certain figure, at which time the pump blades again becomeeifective to move air to the discharge side, reducing the pressure onthe suction side in a matter of seconds to a point where thedifierential is sufiicient to again cause reverse air flow with theattendant squeal.

t is apparent therefore that so long as the pump is able to increase thenegative pressure to a degree sufiicient to produce the requiredpressure differential, a series of objectionable squeals or shrieks willbe produced. The frequency of the squeals will increase as the amount ofair entering the suction line is decreased and the pitch of the squealswill vary as the absolute'volume of the suction lines may be changedthrough the actuation of the various shut-cit valves.

Accordingly, it is an object of this invention to provide means whichwill act in combination with a suction system of the type describedutilizing a centrifugal pump which will effectively stop the squealingwhich up to the present has been considered a necessary evil incident tothe use of this type ofequipment.

A further object of the invention is to provide a specially designedunit which may be attached directly to the discharge side of the suctionpump and in series with the remainder of the outlet piping which will beefiective at once to prevent the disturbing squealing no1se.

These and other objects of the invention will become more apparent asthe description proceeds with the aid of the accompanying drawings inwhich Fig. 1 is a schematic showing of a typical suction system forwaste collecting in a textile mill.

Fig. 2 is an enlarged vertical cross-section of the antisurge valvewhich is installed in the discharge side of the pump.

Fig. 3 is a section on the line 33 of Fig. 2.

In Fig. 1 there is shown a centrifugal vacuum pump 2 driven by a motor 3and having a discharge pipe 4 passing to the atmosphere through the wallof the building 6. The discharge pipe 4 includes a rubber vibrationsleeve 8 and an antisurge valve 10 which will be described moreparticularly hereinafter.

The suction side of the pump includes in the present disclosure thefollowing elements: A gate valve 14, rubber vibration sleeve 16, piping18 leading to two waste receivers 26 and 2.2 connected in parallel,which waste treceivers have at their upper ends shut-ofi valves 24 and26. It is customary to use only one waste receiver at a time, thuspermitting the other to be cleaned. A pipe 28 leads from T 27 to ashut-off valve 3%) beyond which are individual suction pipes 32 and 34utilized in removing waste from the spinning frames 36 or such otherequipment that is to be cleaned.

The pipe 33 leading from T 27 has therein shut-0E valve ll beyond whichare individual suction pipes 42 and 4-4 leading downwardly throughvalves 46 and 48 to the suction nozzles 56 and 52 utilized in cleaningthe cylinders 54 and 56 or the carding engines or other equipment.

The various elements of the system just described are conventionalexcept for the antisurge valve 10, the introduction of which has broughtabout the result of end of section 88 is shaped as at pump 2 will besubstantially clean.

quiet operation which has "heretofore been sought, but never attainedwith this type of equipment. The antisurge valve which isshown in detailin Figs. '2 and'3 will now be described. The valve comprises acylindrical housing of varying dimensions. It'has a lower end 53 adaptedto make connection with the exhaust side of pump 2. This end expandsupwardly in conical formation as at at to connect with an enlargedcylindrical section'62, the two partsbeing secured by a plurality ofbolts 64 which pass through outwardly turned flanges 66 and 68. Theenlarged cylindrical section 62 is necessary to provide for a screen '79that will have suflicient free space therethrough to be at least equalto the area of the connection with the exhaust side of the pump. Thisscreening is secured between the flanges 6-5 and ,68 by the bolts 64.

Within the cylindrical section 62 is a conically shaped section 72having at its bottom end iiange '74 which likewise is secured betweenthe flanges 66 and 635 by the "bolts '64. The upper end oi-the conicalsection '72 terminates in a cylindrical section '76 on which is mounteda pressure operated one-way valve unit. This valve consists of acylindrical sleeve 73 with an inturned flange 79 which is placed on theupper end of the cylindrical portion 76. At one side is an extension forsupporting a hinge 80 to which is pivoted a valve 82 which valve when inhorizontal position as shown in Figs. 2 and 3 is closed and will preventthe flow of air downwardly in the reverse direction through pipe 4. Whenthe pressure on the under side of valve 82 exceeds that above, the

' valve will then swing to open position as shown in the dotted lines inFig. 2, thus permitting air to flow upwardly through the unit as it isdischarged from pump 2.

The upper end of cylindrical section 62 has an .out wardly turned flange84 to which is secured the flange 86 of the conical section 38 by thebolts 99. The upper 92 for connection to the pipe 4. a

The weight of valve 82 is relatively small and because of itsappreciable area only a small pressure differential is required to openit to permit air to flow from the exhaust side of the pump at 50 throughvalve 82 to the pipe'4 leading to the outside atmosphere. That is tosay, the introduction of the valve 82 has very little efiect on thenormal operating efficiency of 'the system in" that the additional backpressure caused by valve 82 is, for practical purposes, negligible.

.The mode of operation of the invention is as follows:

Let us assume that all parts of the mill, for example,'

the spinning room, the weave room, the card room and the picker room,are to be cleaned at the same time. In such case, a maximum amount ofair will be drawn by the vacuum pump 2 and expelled to the atmospherethrough pipe 4. Valves 14, 24, 3G and 40 will be'opened, thus creatinganegative pressure in the piping which will permit the cleaning of thevarious machines through the use of the subsidiary connecting pipes 32.,3 42 and 44 -and other piping not shown which would lead to the weaveroom and picker room. The waste picked up from the various machines iscarried through pipes 28 and 38 to be deposited in one or both of thereceivers 2t) and 22 in which there are filters so that the air leavingreceivers and passing through pipe it; to the suction As the pump 2continues in operation, the negative pressure in the pipe 18 increasesto a point where the differential in pressure between that of pipe 13and that on the exhaust side of the pump is such that in the absence ofthe antisurge valve 19, atmospheric air in pipe 4 will reverse itsdirection, flow back into pump 2 and thence back into line 18 with theattendant objectionable squeal until such time as the pressuredifferential is reduced so that the pump again becomes elfective tocause air fiow in the normal direction. I

The introduction of the antisurge valve 10, however,

gran-lea 'at a position immediately above the discharge side ofthe pump.has eliminated this troublesome noise. The reason for this is that whilethe pressure of the air within the very short section of pipe 58 and thelower part of the surge valve unit below the valve 32 is of such smallvolume that even though it may start bachwardly through the pump whenthe pressure differential cecomes great enough, the pressure falls belowatmospheric rapidly because of thesmall air volume, and hence therequired pressure differential necessary to initiate and continue thisbackward flow is immediately eliminated. That is to say, the reverseflow stops almost immediately after startingand therefore no soundis'caused. The amount of air that can flow backward is limited by theoperation of valve 82. and the resultant immediate pressure drop. Assoon as any backward flow in pipe 58 commences, the air in pipe atinfluenced by the pressure drop in 53 likewise moves in the reversedirection. This in turn instantly closes valve 82 or maintains it closedif it was in that position, thus limiting the air that can flowbackerate continuously at full efliciency without objection by.

persons in the neighborhood. 7

"From the foregoing explanation, it can be seen that the improvementresides in the combination of elements which includes therein a pressureoperated one-way valve that is located so close to the exhaust side ofthe vacuum pump that there will be an insufficient volume of air betweenthe valveand the pump to cause any appreciable reverse flow to the pumpafter the pressure ditferential has become great enough to cause theinitiation of such fiow.

It should further be pointed out that the number of squeals occurringper minute under the prior practice varied with the total volume ofpiping in use on the suc? tion side of the pump. Thegreater the volumeof the piping, the lower the number of squeals per minute. The

less the volume, the higher the number of squeals per the valve 39 wereclosed, cutting oir all the suction piping fromthe spinning room, thenthe frequency ofthe squeals would immediately increase.

Now, however, by the introduction of the *antisurge valve '10, squealingis entirely eliminated regardles of the extent of the suction system inuse at any time.

While the explanation of the improved results obtained 7 as stated aboveis believed to be correct, it should be I claim:

1. In a vacuum cleaning system comprising a centrifugal vacuum pump, asuction line and an exhaust line, a one way valve unit in said exhaustline located close to said pump, said valve unit comprising an en largedcasing having a cross-sectional area which is larger than thecross-sectional area of the portion of the exhaust line to which saidunit is connected, means forming a passage extending within said casing,the end of which has an opening forming a valve seat, said passage meanscommunicating with the exhaust line and being spaced from the wall ofthe center section of the casing, and a pressure operated valve movableupwardly away from and downwardly toward said seat, said valve beingmoved downwardly to said closed position in response to initiation ofbackward flow, the volume of the exhaust line between said valve andpump when said valve is closed being insufficient to provide a back flowof gas through said pump which will cause undesirable shriek when thepressure differential between the suction and pressure sides of saidpump causes backward flow to occur.

2. A system according to claim 1 wherein said passage mean is of varyingcross-sectional size in the direction of gas flow.

3. A system according to claim 2 wherein said passage eans is conical inshape.

4. A system according to claim 1 wherein said pressure operated valvewhen full open having substantially the capacity of said exhaust line.

5. A vacuum cleaning system comprising 'a centrifugal vacuum pump, asuction line and an exhaust line, said exhaust line including therein aone-way valve unit located close to said pump, said valve unitcomprising an enlarged casing, two end sections, one of diminishingcross-sectional area in the direction of gas flow and the other ofincreasing cross-sectional area in the direction of gas flow, and acentral enlarged section connecting said end sections, said enlargedcenter section and the wider ends of said end sections being larger incrosssectional area than the portion of the exhaust line to which saidunit is connected, means forming a passage within said casing, saidpassage means being of varying cross-sectional size in the direction ofgas flow and the end of which has an opening forming a valve seat, saidpassage means communicating with the exhaust line and being spaced fromthe wall of the center section, and a pressure operated valvecooperating with said valve seat permitting substantial flow of air awayfrom said pump only.

6. A pneumatic system comprising a centrifugal pump, an exhaust line and.a valve unit in the exhaust line, said unit comprising a firstcylindrical end of substantially the size of the exhaust pipe to whichit is to be connected, said end connected to a conical sectionconnecting in turn with an enlarged cylindrical center section, a secondconical section leading from said center section to a second cylindricalend which is substantially the same size as said first end, a conicalbaffle with a central opening located within said cylindrical sectionand connected thereto, a pressure operated valve mounted in said openingwith said valve movable from closed to open position in the direction ofsaid second end.

7. A system as set forth in claim 6, said valve being pivoted on saidbaffie and positioned to swing in a vertical arc.

References Cited in the file of this patent UNITED STATES PATENTS1,216,119 Hinz Feb. 13, 19-17 1,232,180 Barnes July 3, 1917 1,267,880McBride May 28, 1918 1,348,562 Hauser Aug. 3, 1920 2,007,777 StanderwickJuly 9, 1935 2,055,193 Bischoff Sept. 22, 1936

